Add IsSorted tests and fix bug

Source/Singulink.Globalization.Currency/SortedMoneySet.cs

@@ -647,7 +647,7 @@ private void ThrowCurrenciesDisallowed(List<Currency> currencies, string paramNa
 #endif
 
     /// <inheritdoc/>
-    bool IReadOnlyMoneySet.IsSorted => false;
+    bool IReadOnlyMoneySet.IsSorted => true;
 
     /// <inheritdoc/>
     bool ICollection<Money>.IsReadOnly => false;

Tests/Singulink.Globalization.Currency.Tests/MoneySetTests/IsSorted.cs

@@ -0,0 +1,25 @@
+namespace Singulink.Globalization.Tests.MoneySetTests;
+
+[PrefixTestClass]
+public class IsSorted
+{
+    [TestMethod]
+    public void Sorted_UnsortedSets_IsFalse()
+    {
+        IReadOnlyMoneySet sortedMoneySet = new MoneySet();
+        IReadOnlyMoneySet immutableSortedMoneySet = ImmutableMoneySet.Create();
+
+        sortedMoneySet.IsSorted.ShouldBeFalse();
+        immutableSortedMoneySet.IsSorted.ShouldBeFalse();
+    }
+
+    [TestMethod]
+    public void Sorted_SortedSets_IsTrue()
+    {
+        IReadOnlyMoneySet sortedMoneySet = new SortedMoneySet();
+        IReadOnlyMoneySet immutableSortedMoneySet = ImmutableSortedMoneySet.Create();
+
+        sortedMoneySet.IsSorted.ShouldBeTrue();
+        immutableSortedMoneySet.IsSorted.ShouldBeTrue();
+    }
+}